Automatic audiometer



Feb. 12, 1957 F. A. BROGAN 2,781,416

AUTOMATIC AUDIOMETER Filed July 12, 1955 3 Sheets-Sheet 1 FMH mp4@ IN V EN TOR.

F. A. BROGAN AUTOMATIC UDIOMETER Feb. l2, 1957 5 Sheets-Sheet 2 Filed July l2, 1955 Feb. 12, 1957 F. A. BROGAN AUTOMATIC AUDIOMETER 3 Sheets-Sheet 5 Filed July 12, 1955 NON R B" lll United States Patent AUTOMATIC AUDIOMETER Francis A. Brogan, San Antonio, Tex., assigner to the United States of America as represented by the Secretary of the Air Force Application July 12, 1955, Serial No. 521,653

11 Claims. (Cl. 179-1) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

The present invention relates to an automatic audiometer and particularly to an audiometer actuated by the patients response to give a printed record of the hearing response of both ears of the patient.

In the armed forces there is a distinct need for a knowledge of an individuals hearing status at the time of induction to determine whether there has been any service connected loss of hearing at a later time. The making of an audiogram employing a conventional manually actuated audiometer requires considerable skill and training and a skilled operator can test only approximately one hundred persons per day. The supply of trained personnel is inadequate for making tests of very large numbers of patients in a short time.

The present invention provides a means of conducting screening audiometric tests on a large number of people in a short time, each individual test taking only a few minutes and the printed record of each test can be transferred to a conventional audiogram card for a permanent record. Those cases found to have a serious hearing impairment can then be referred to a skilled audiometer operator or to an otologist for more extensive testing and treatment.

In accordance with the present invention a conventional audio oscillator unit capable of supplying a plurality of pure tone outputs of different frequency is provided, each output being passed through a respective calibrating attenuator to adjust the output to the normal standard threshold of hearing for the particular frequency. A stepping switch is automatically sequentially switched from one frequency to another. A separate stepping switch operates to attenuate each tone through a series of discrete steps from a level of, for example, 40 decibels above to 10 decibels below the normal hearing threshold. The tones are presented to a patient for a predetermined interval, after which there is a predetermined scoring interval with the final score being automatically recorded on a record strip. A programming switching device controls the ltone presentations, the scoring period, record paper movement and printing of the record. p

After initiating the start of the test the` patient is presented with the highest intensity tone at the first frequency in the right earphone and if a response is made within the scoring period of say two seconds the intensity stepping switch steps the intensity down through a ten decibel range. This processv continues so long as a proper response is made until a predetermined number of tone presentations N, for example ve, have been made. The tone intensity will -then correspond to the normal threshold of hearing at that frequency. The next three tone presentations are made with a ve decibel drop and each is printed on a record tope.

In the event of a closure of the response switch prior a 2,781,416 Ice Patented Feb. 12, 1957 to the scoring period, or a failure to respond, the intensity stepping switch reverses to the next higher tone except for the first tone presented so that after N presentations the patient may not have arrived at the normal threshold of hearing and the next three presentations will then determine his actual threshold since the intensity will reverse on failure or advance tive decibels on proper response and all are printed. After the N+3 tone presentation a relay system advances the frequency stepping switch to the next step and the process is repeated for each of the audio frequencies. At the termination of the tone presentation program for each frequency the series is repeated connecting the left earphone. At the conclusion of the tests the circuits are then de-energized and the system conditioned for a new test. A printed record will be had indicating the threshold of hearing of each ear at each of the selected test frequencies and the data can later be transferred to a standard audiogram card or placed on a punched card record.

It is accordingly an object of the invention to provide an improved audiometer.

Itis a further object to provide an automatic recording audiometer.

It is another object to provide an audiometer responsive to the patients response.

Although the invention has been briefly outlined above, all of the features of the invention will be better apparent by reference to the description hereinafter given and to the appended drawings in which:

Fig. l is a block diagram of the components of the invention;

Fig. 2 is a perspective view of a programming control device employed in the invention; Y

Fig. 3 is a front elevation of the printing device;

Fig. 4 is a schematic view of the record strip feed mechanism;

Fig. 5 is a perspective View of the printer with parts broken away;

` Fig. 6 is a schematic perspective view of the stepping switch with parts broken away and in section;

Fig. 7 is a general circuit diagram; and

Fig. 8 is a graphical presentation of the time intervals.

Referring now to Fig. l, the invention in general comprises a test set including a headset 10 having right and left earphones, 12 and 14, connected to a junction box 16 which has mounted thereon a push button 18 for starting the test, an indicator light 20 which when lit indicates that no test is in progress and a subjects response pushbutton switch 22 connected to the junction box 16 by a cable 24. The above apparatus is positioned in a sound-proof room or booth 26 indicated in dotted mes.

A.. control set including a tone generator 30, a programing device 50 and a recording device are located externally of the booth 26 and connected to the test set by a cable 28.

The audio tone generator generally indicated by the reference numeral 30 is capable of producing a desired number of pure audio tones `of different frequency. In the present case five different frequencies are employed namely,- 250, 500, 1000, 2000 and 4000 cycles per second which are standard frequencies employed in audiometry to cover the normal hearing range. The frequency vrange could be extended if desired.

The cable 28 is also connected to a programming switch generally indicated by the reference numeral 50 which includes a cam disc 54 driven by a constant speed synchronous motor 51 at a rate of one revolution per minute. The programmer 50 determines the time of transmission of each tone, the scoring period within which a proper response must be made and energizes Ithe paper moving and record stamping solenoids iny the recorder unit.

The cable also interconnects a relay console generally indicated'by the referencen character 32 whichcontains all ofthe relays, a rotary steppingV switch for'counting the number of -tonev presentations, the attenuatorsfor adjustng theaudio` output of thel tone generator for the normal threshold of hearing for each earphone, 12 orV 14, ateach selected frequency and a three bank rotary stepping switch for frequency selection.

Apower-supplyunit generally indicated by thereferencenumeral 34fw-hieh includesa transformer 2id-and suitable'rectiers 33-suppliest6i3 volt A. C. power to the push to start-button' switch lld;v indicator: lamp Zilland patientisrresponseswitch 22 inthe test booth 26, 110' volt D. C. power foroperation'ofitherotary stepping switches anda110`volt A; C. power for relay operation.

Atrecorder or printer generallywindicatedby thereferencenumeral 7 di completesthef-v system:A assembly and is operative aftera predetermined number offtone presentations: have: been made to print 'thef last three: tone: intensity values for eac-hzfrequency. 'lhcprinter type-bars121 are positioned byy the rotaryi intensity;l selector switch 135 which is mounted on the printerpanel 72.

Prior to describing..theyspecic. circuitryldetails, the programmer 50 and printer 7i) will be described;Y

Referring: to Fig; 2 the'programmery isf-generally indicated by the reference numeralfiiand; includesa: base 49.- on which is mounted a gearedfhead synchronous .mo tor 51 having ashaft 52V driven ata1constantspeed of, for example, one revolutiony per minute; On t-hegshaft 52 is mounted aA timing disc 54,v whichl isiprovided with aseries of spaced holesSS adjacent itsperiphery. A plurality of pairs of cam lugs 56 and 5S are mounted' on the disc 54,.one-of eachpair, ,56 for actuating a tone switch 57 and the other Sitter actuatinga score switch 59, the. cams 56a-nd SSAhave their leadingcdges in alignment but. cams- 56.have `an arcuate length of one-half that oflcams 58. The pairs of cams 55 and Sd-arefran-A domly spaced to prevent patient synchronism. The tone switch 57 andscore switch 59 are mounted adjacent'the edgeof the disc 54-and eachprovided with roller actuating arms 40 and 42 which are engaged by the respective cams 56 and 58.. The switches 57 and 59 are of the Wellknown snap actiontype and are closed at the same time by the cams 56and 58 (as .shown in Fig. 8)the tone switch. S7 remaining closed for a perioden ofonesecond and the score switch 59 remaining closed for aperti-od 42`of'two seconds when respectively actuated bythe cams 56; and 53; The time duration di) and 42 of closure of the tone and' score switches may be varied from. that here' employed il.VA so desired.

Screws 6i) are arranged in substantially annular projecting relation on one face ofthe disc 54' and are adapted to actuate a paper move roller actuating switch 61, and similar screws 62 arranged in alignmentwith. thescrews i60 actuate a similar stamp switch63. The screws 60, and 62- are-positionedjust aft ofthe trailing edge of the cams S and the switches 61 and 63 are shifted relative to each other .so that the time duration of switch closure is' asl shown in Fig. 8. In this ligure it is seen that tone switch 56 and score switch; 5S close together with tone durationV d@ of onei second and score duration 42 oftwo seconds. After a one-tenth secondk delay 44 the move switch: 61 isv elo 'ed for a one-tenth second period 45 and after a. corresponding delay 46- the .stamp switch 63 is closed4 for a one-tenth second period 47. Suitable conductors (not shown) in cable 2.55 serve to connect' theprogrammer switches tothe other units of thezsystem;

The recorder or printing mechanism isV shown in Figs. 3, 4 and 5. As seen in 3, it. is generally indicated by the reference, numeral 7d and. comprises a base 'Z1 having. secured thereto a vertical panel 72 lon which is mounted by means of a removable stud '73 a paper roll 74. Paper strip 75 from the roll 7d passesA over a spring pressed tension roller 76 and over a flanged guide roller 77. A removabley stud 'It serves. to mou-nt a roll 79 ..of carbon paper strip 80 which is led over a guide roller 82 to emerge immediatclybeneath the paper strip 75. The paper and carbon strips 75 and 8i! pass through stationary guides 84 and over a flanged guide roller S5. The paper and carbon strips are then separated, the paper passing over a feed roller E6 `and under a pressure roller 87 andthe carbon strip 8d passing over a feed roller ":3V and under a pressure roller 8,2

As seen in Fig. 4, the paper` feed roller 3.6 .is mounted on a shaft Stb which passes throughthe panel 72 and has a gearA 91 fixed thereonwhich meshcswith an idler gear 92 Which in turn `drives a gear 93rnountcd on a shaft 94 which in turndrivesithe, carboni stripfeed roller 38 in the same direction andvat the same speed as paper feed `roller Se. An electrical solenoidlilil providedwith a spring pressed plunger 10i is suitably supported from the rear of panel 7l Fig, 3, and the plunger' guided by a guide lili; The plungerv is provided with an arm 103 which carries a pawl i641; pivoted thereon. The pawl 104 is suitably biased by a spring'iso as tocngagc a Itoothed ratchet wheel 196 fixed on the Macworld/.cidre shaft tlanddriving the same. Eachtimethc solenoid coil lili)` is energized the plunger.V ldlisretracted upward causing pawlllili'to advance the ratchet whceliild which drives .shaft 9@ andifecd rolld-to-movethe paper strip'75and through gearing-to drive shaft @d and feed lroller SS to move the carbonstrip'; The paper strip 75 after passing between feed. roller S5 andprcssure roller t?? passes through. a conventionah spring loaded manually actuated paper cut-offV ldd (Fig. 3).

As-seen in Figs. 3 and 5; arotatab-le printing head .is-.mounted on the front side of the panelf'. of thc printer assemblyldV and has` typcbars 2.2L mounted on theexterior arcuate surface thereof. ThereA are e.even type bars i having numerical.indicia rangingfrom 4G decibelsthrough zero to minus lOdecibel-sin steps-,of Iivefdecibclsv corresponding to the normalrange of intensity. employeddn audiomctric testing. The type bars 121. are adaptedtoprint by pressure on thccarbonstrip and Rall@ Asseenin Fig. 5,-a `stamp solenoid coil'lZS adapted to befmounted on the rear ofl the panel 71, Fig. 3, .ispro vided'with-a spriugloaded plunger L26 and guide 127. The solenoid 125 when energized moves the plunger 12,6V downward moving the integral arm 1,23 withit. The arm 12S-extends througha slot 1Z9.in the panelfl., Fig.- 3, and hasnl stamp mounted on its youterendand adapted to strikethe-paper strip 75 and carbon strip 80.,.onftothat type bar 12]; which happens to be located immediately beneaththe stampy 130.

Asl seenin Figs. 3 and. 5,`therota1y printing head 120 isxed on; the outer end of a shaft ldwhich forms a part, of, an intensity selector switch assembly generally indicated-,by` thercference character 1:35, Eig.. 6. The shaft 1&4. extends through the panel 71, Figy', withV the printinghead positioned on the front side; of. the.. panel as previously described.

The intensity selector switch assembly .1.55 schematically illustrated, i-n Fig. 6, is mounted on th?. reni' of thc panelr72l (Fig. 3) of the, printer unit 79. The switch which is, of a commercially available typev includes anpair; of actuating coilsA one 135B for forwardoperation andthe ,otherlSSR for reverse operation, the coils being shown in` phantom. Each coil isprovided with a pivoted armature, 136 provided withl a verticaly extension. 13'/ which carriesa spring biased actuating p awl 3.38 adapted to, engage a toothed ratchet. wheel 139 to cause forward o rl lreverse actuationthereof and to drive the shaft 13d in a corresponding; direction, A frictionl datent 1.4i? is provided, and in addition teeth juil. on each vertical armature extension, 128 engage theratchct jto limit the rotation thereof to, a predeterminednumber of teeth in either direction. Pins 142 and 144. on thel ratchet wheel 139 are. adapted, to actu-ate limit switches litt and. Ms'. A four bank, twelve position switch is mounted on the tors 180 and contact eleven dead. -1605-2 on bank 2 is connected by conductor- 174 in tuner end of shaft 134, the switch blades 135s being fixed on the shaft 134 and each engaging one of the banks of contacts 135C. Eleven contacts on each bank are employed one corresponding to each tone intensity. The corresponding active contacts on each bank are connected in parallel so as to reduce contact resistance to a negligible value. Each time the coil 135F is energized the switch blades 135S are advanced to the next contact in each bank each contact representing a 5 decibel stepdown and coil 135K when energized will cause a stepping of one contact space in the reverse direction. When the limit is reached in the forward direction limit switch 146 opens the circuit. Limit switch 148 opens the circuit in the reverse direction. The reversing coill 135R may be pulsed by an interrupter 150 for rapid resetting. The intensity selector switch 135 is operated by 110 volt direct current which is also employed to operate the frequency selector and to count stepping switches.

With reference to Fig. 7 the relation of the tone generator frequency selector switch 160 and intensity selector switch 135 is made clear in the general circuit diagram. In this figure the audio tone generator generally indicated by the reference numeral 30 which as previously described is of conventional character being a vacuum tube oscillator type capable of producing five or more discrete audio frequency outputs. The outputs appear on the respective conductors 151 to 155 inclusive and are 250, 500, 1000, 2000, and 4000 cycles per second. The tone generator is connected to ground at 156 and conductors 157 and 158 connect the generator to a tone interruptor blade 276 which permits audio output only when the relay 272 is closed.

Each of the output conductors 151 to 155 is connected to a pair of attenuators arranged in a bank and generally indicated by the reference numeral 180. The conductor 151 is connected to the rst and sixth attenuators, 152 to the second and seventh, etc. The attenuators are each adjustable 500 ohm T pads and are employed to calibrate the earphones 12 or 14 so that the audio output at each frequency with the intensity selector switch 135 at the zero level will correspond to the normal threshold of hearing at that frequency. In order tof avoid the use of expensive calibrated earphones separate attenuators 180 are used for each frequency for left and right earphones permitting standard Air Force headsets to be employed.

A three bank rotary stepping switch is provided for frequency selection and is generally indicated in Fig. 7 as 160 and identical in construction to the intensity selector switch 135 of Fig. 6 previously described. The coil 16012 causes forward operation of the switch to increase frequency and a lreverse operating coil 1601?. for resetting the switch to the zero or initial position. The forward coil 160F has a limit switch 162 and the reversing coil has an interrupter 164 and limit switch 166 associated 'therewith the -interrupter pulsing the switch -coil 160R for rapid resetting.

The contacts 160C-1 in bank l of switch 160, twelve in number have the iirst or zero contact dead, the next five contacts connected in parallel to conductor 168 which leads to the right earphone 12, contacts six A through ten connected in parallel by conductor 170 to the left earphone 14 and the eleventh contact dead.V The switch blade 1608-1 on bank l connects by conductor 172 to the switch blade assembly 1358 of the intensity selector switch 135 here shown. schematically but previously described above with reference to Fig. 6.

The contacts 160C-2 of bank 2 .of switch 160 are twelve in number .with the zero contact dead, contacts one through ten each connected to one of the attenua- The switch blade parallel to a bank of intensity attenuators generally indicated by the reference numeral 176, The attenuato-rs ',176 are each connected to one of the'eleven active contacts 135C of the intensity selector switch 135 and serve to respectively reduce the audio tone intensity in steps of ive decibels from a level of 40 decibels above the normal threshold to ten decibels below the zero or normal threshold.

The contacts 160C-3 on the third bank of the switch 160, Fig. 7, are all dead except the zero and first contacts which respectively function in de-energizing the system and energizing the system respectively and the eleventh contact which serves in a resetting operation all to be later described. The switch blade 1608-3 of bank 3 of switch 160 is connected to a point A or return side of the volt power supply to serve as a common when the common point of other return circuits is opened in de-energizing the system.

By reference to the composite circuit diagram, Fig. 7, it will be evident that when the stepping or frequency selector switch 160 is energized through its coil 160F the switch blades will move on all three banks when the frequency equals zero or start position to the rst active position. When the audio tone generator 30 is rendered operative by a circuit being completed through conducto-rs 157 and 158 by closing switch 159 a tone output at the first frequency of 250 cycles per sec. will appear on conductor 151 and will pass through the first of the attenuato-rs 180, switch blade 1608-2 `on bank 2, conductor 174 and through the first of the intensity attenuators 176 associated with the intensity selector switch 135. The 250 cycle tone will be attenutated to a level of forty decibels above the normal threshold of hearing for that frequency and will pass from the first contact on intensity selector switch to switch blades 13S-S and conductor 172 to the switch blade 1608-1 on bank l of frequency selector switch 160. The tone will then pass to the first active contact on bank 1 to conductor 160 and to the right earphone 12. As will be later explained, each successful patient response will send two pulses to the coil 135F of the intensity selector switch 135 causing the switch blade 1358 to advance two contact spaces for dropping the intensity ten decibels. When a total of eight tone presentations has been made the frequency selector switch will step one contact space and the intensity selector switch is reset to start the second series of tone presentations at a frequency of 500 cycles per second. After the fifth frequency the selector switch arm 1608-1 will transfer to the left earphone 14 and the frequency series will repeat beginning with the 250 cycle tone.

A counter switch 190 is similar to switches 135 and and'has a forward operating coil 190-F and a reverse operating coil -R. Switch blade 190-9 is connected to the common circuit A and successively engages the contacts 190C. A forward limit switch 192 limits the forward progression of the switch 190 and a limit switch 194 stops the switch return at the zero position. An interrupter 196 facilitates a rapid return to the zero position. rEhe primary group, herein ve, of the contacts is open or disconnected. A second group, herein three, is connected in parallel and controls the energization of the actuating coil 200 of the printer control relay 202.

The control circuitry is best understood in connection with the operation .of the system.

In the operation of the audiometer 110 volt alternating current is connected to vthe principal pair of conductors 204 and 206 having terminals A and B. All switches are actuated to zero position at which time blade 1608-3 of switch 160 will be in contact with contact 160C-3-0. Blade 1605-3 is directly connected to conductor terminal A while rectifier 38 is fed across conductors 204 yand 206 to supply 110 D. C. to terminal C and a return connection through conductor 204 to terminal A. Likewise the primary winding 203 of transformer 36 is con- Anected across conductors 204 and 206 to energize secondary winding 210 at 6.3 volts which appears across common terminal D and conductor 212.

arf-aigue The; engagement f; blade, 160,5.-3 with @met 1.6.9Q-.3-.0f hirsize wil- 214 O f relay 211 fhwgh'ef" Initial B rthelcohnductor 218l and the blade 160C- 3-0 to terminal Energizatin ofcoil 214 movesthfe switch b lades 220,222 and 224 of relay 216 into front position disconnecting terminalY B from the audiometer and terminal' A from common terminalV Awhile `front contact 226 engaged'by blade 221)0 applies the potentialfbetween terminal D and conductor 21210v the signal lampy 20 thus indicating that the audiometer is de-energized;

The patient enters` the booth 26 andA adjusts the headsetl-lafter which the patient actuates the starter switch 18 which connects coil232l ofrelay 234 between conductor 212 and terminalD thus momentarily. energizing relay 234 to close blade 236 andr energizing coil- 233 of relay 240ebetween terminals B^and- IAby blade 242 of relayy 244, conductor 218?, contact 160C-3-0 and blade 160MS-3.A Energizing coilV 233` closes blades 246 and243. Closing blade 246l locks in coil 238` between terminals B and A= through blades 242and'246- after which release of start button 1S-deenergizes coil 232`moving blade 236 to. open position. Closing blade 24S energiz'esforward stepping coil 1601? offrequency selector switch 160- between terminals C and-A by way of blade 2481, conductor 250 and limit switch 162` causing selector switch. to move onestep forward moving blades 11608-1, from contact- 16ilC-1-0-tocontactleiC-l-l, blade 1608-2- from contact.160C-2-1l tocontact 160C-2-1 and blade 1608-3 from contact 16iC-3-0 tocontact 160C-3-1. Moving blade16ilS-3 from contact 160C-3-0 de-energizes coil 214: so. that relay216 opens and. blade 220l engages back contacts. 252 connecting conductor. 212 to the 6.3 volt terminal252 and de-energizing.signal'lamp 2.0.inforrning theipatient that thev recording is about to begin, blade 222 engages back contact. 254 and connects terminal A 1 to A,- also, blade 224 engages backv contact. 256 connecting coil 258 of. relay 261B.. to contact 16llC-3-11 by wayofconductor 262. The closing :of blade 222 connects the, common return and starts. motor 51 which rotates cam disc 5.4.

The arrival of blade 1605-3 at contact 1 6C-3-1 energizes coil266 of relay 244 and opens blade 242 thus deenergizing coil 238 so thatv relay 240 opens blades 246 and 248 resetting the starting circuit.

Simultaneously blades lllS-l and 1605-2, arrive at contacts 16ilC-1-1` and 160C-2-1, respectively. This connects the tone generator 30 by conductor151, T-attenuator 18d-1, blade 1668-2, conductor 174, attenuator 176-1, blade 13S-S, conductor 172, blade 1608-1 and conductor 168, tor right earphone 12 of headset 1i).

RotationV of, cam disc 54 causes cams 56. and 53 to si- I multaneously. close switches S7 and S9. Closing switch -7 energiziesj coil 270 of relay 272, which then moves blades 2.74, Z76and278 tofront position. Closing blade 274;, energizes coil 191F of count switch 1% through limit switch'192so that count switch blade 19338 advances i -closesrits blades290y and 2.92. Closingy blade 291i applies potential tov coil 294 of resetting relay 296 and coil 2% of relay 300 which however'. remain de-energized until count switch 190 reaches its iinal contact. Closing blade 292. opens back` Contact 30,2 preventing energization of coil 304l of relay' 396 and closing frontl contact 3618 to connect to coil 282-y oi relay 254 through back contact 310 and blade 312. @f relay 396- At the end of. one second cam 56 opens switch 57 whieh releases blade 276 to terminatethfpplicationof the'tonezfto-vtlephone 12 and blade 273 will engage-bacli lcontact 2,80 to completean activating circuit for coil 282 by'way of bladesv 3112 and to blade 314 or patient response relay 316.

The further operation of` thev device isdependenLon thefr'sponse of.. the patient which maybe of.V eitherof, the following types l 1-, Successful: "in which. the patient hears the tone. and responds inthe properscore interval.

2; Failure: in. which the patient fails. to respond in the. score: interval. l

3. Guess:v in. which the patient responds at other, than the score. interval. Cheating. is. substantially. defeated by the unequaLspacing. of the. cams S6 and 58.

(l) ln successful operation, i. e., if. during the score interval after the. closing ofl switch, 57l and before the opening offswitch59, the patient closesresponse button- 22. energizing..coil. 318A4 of response. relay 316 from the 6.3 terminal through blade, 320L of. relay 322through b utton 22y to return terminal D. Energizingcoil 31S causes relay 316 to closeblade324.locking,in relay 3164 and cornpleting, the, activating. circuit. of coil 282, through back contact. 326; and blade 328 of relay 322. to terminal B. r[his ene1gizes.coil:282 which causes. relay. 284 to close blade 3301 and lock itself' in from, terminal B through bladesl 330 and 27 8 to, terminal A, and movingblade 332 from back. Contact 3,34 to front contact 336 connecting coil;v 13513,-` from terminal-A through limit switchl 146 and blade, 332 to. blade 3600i relay 322.

At the.end of interval 42 switch 59 will open deenergizingcoil; 286A opening blade29()V and moving blade 292 from contacty 30,8y toback. contact 3112 energizing coil 304 from terminal A by way of bladeV 292, blade 314 and bladel328,L toA terminal B. Relay 306 then closes` blade 340 andy locksy itself.A in by way of blade 328v and also moves blade 312 out of engagement with back contact 310.

At the` end of interval 44V cam 60 closes move switch 61; energizing coil 342 of; relay 3,44 which closes blades 346and 34S. Closingblade 346-energizes coil 135F`from terminal; G by way, of blade 346, blade 332 and limit switch 146 toterminal A and'. moves blade 1353 forward oney step` Closing blade. 348' connects terminal B over blade 348 to blade 350 of relay 202 which.- is. open because ofthepositionv of. switch 190.

At theendl of: interval 45 switchl 61 opensv de-energizing coil. 342 andallowing blades 346 and 348 of, relay 344 to open.

At thel end of interval 4,6.cam 62 closes stamp switch 63 energizing coil 352 of relay 322 which moves blade 320 out of engagement with back contact 354 resetting the response system. Blade 32S moves from back contact 326;, defenergizin" coil Sil-il resetting relay 306, to front contact 356 connecting terminal B over blade 328 to blade 3530i relay 262. Also, closing blade 36) connects terminal Cover blade 362 of relay 2112, blade 360, blade 332, limit switch 146 and coil 1351T of switch 135 to terminal A causing a second step movement of switch 135.

At the end of interval 47:switch 63 opens de-energizing coil 352 allowing the response system to return to recycling condition.

Assuming that the patients hearing is sumciently acute to respond overv the entire test range, the selector switch 135 will move two steps until blade 1998 of count switch 19harrives at contact 19ilC-6 at which time coil 200 of relay 2112 will be energized by way of terminal B, contact 19ilC-'6 and blade 1968 to terminal A. Energizing coil Zilli closes blades. 35i) and 353 and moves blade 362. out ofengagement with back contact 364 inhibiting the second pulse to coil 1351? so that switch 135 moves only one stepper cycle. With switch 191i close closing of move switch 61 causes energization of paper feed solenoid Miti from terminal B by way of blades 348 and' 350V to Vterminal A causing a paper feed at each cycle. Also, closing of recording switch 63 causes energization of stamp solenoid from terminal B over blade 32S, back contact 356 and blade 358 to terminal A causingplunge'r 126 to move presser 130 into printing relation with thc type bars 121. Arrival of blade 190s at contact 19C-9 connects coils 294 and 298 to terminal A so that closing of switch 59 energizes relays 296 and 300 from terminal B over blade 290. Relay 300 closes blade 368 to lock in relays 300 and 296, also closes blade 370 to apply an impulse to paper feed solenoid 100 to move the printing out of the printer 70 to takeoff device 110. Relay 296 closes blades 372, 374 and 376. Closing blade 372 connects terminal C over blade 372, interrupter 196, limit switch 194 and coil 190k to terminal A. The impulses 196 produces a series of impulses to step the switch 190 in reverse until limit switch 194 breaks the circuit. Closing blade 374 applies an impulse from terminal C over blade 374 and limit switch 162 through coil 160F to terminal A to cause switch 160 to move forward one step to connect another tone to the test phone. Closing of blade 376 connects terminal C over blade 376, interrupter 150, limit switch 14S and coil 135R to terminal A, the interruptor 150 providing impulses until the circuit is interrupted by limit switch 14S.

(2) Failure; if total will prevent forward stepping of switch 135 so that a final printing of 40 decibels indicates total failure. However, most failures are partial and occur after switch 135 has made one or more pairs of forward steps. Failure to actuate button 22 maintains coil 2S2 de-energized so that blade 332 remains in engagement with back contact 334 whereby closing of blade 346 in response to closing of switch 61 energizes coil 135 from terminal C by way of blade 346, blade 332, back Contact 334, limit switch 148 and coil 135R to terminal A causing a step in reverse of selector switch 135. lf blade 362 is in engagement with back contact 364 closing of switch 63 will likewise cause a reverse step returning the setting to the last heard tone application. After relay 202 is energized, blade 362 will be out of engagement with back contact 364 so that switch 135 will advance or reverse only in single steps thus insuring that the printer 70 will record the lowest re spouse level.

(3) Guess; if the patient presses button 22 at a time when relay 288 is not energized relay 306 will be energized locking itself in and opening blade 312 thus preventing energization of relay 284 so that switch 135 will be reversely moved in the same way that failure causes reverse stepping.

After the series of tones, herein indicated as tive, have been presented to one ear, the switch 160 will connect the tone application to the other ear. Upon the completion of tone applications to both ears blade 160S-3 arrives `at contact 16GC311 energizing coil 258 of relay 260 which locks itself in by blade 378 and applies potenv tial from terminal C by Way of blade 380, interruptor 164, limit switch 166 and coil MBR to terminal A. The interrupter 164 applies successive pulses until blade 1608-3 engages contact 160C-3-0 which energizes coil 214 of relay 216 which closes blades 220, 222 and 224 to de-energize the device and energize signal lamp 20.

It will be apparent that the device automatically nds and records a patients auditory perception level at a plurality of frequencies.

For purposes of exemplication, a specilic embodiment of the invention has been illustrated and described according to the best present understanding thereof. However, it will be apparent that many changes and modifications in the construction and arrangement of the components of the device may be readily resorted to within the true spirit and scope of the invention.

= I claim: .1. An audiometer comprising a tone generator, a tone reproducer adapted to be app-lied to the'ear of a patient, an attenuator connected between saidgenerator and said reproducer and .operable to matchsaid generator and said reproducer, a switching device, means'controlled by said switching device'for intermittently applying atone from lsaid generator to Said reproducer, a groupfof attenuators vi0 operable to provide a plurality of toneintensity levels,` an intensity selector switch operable to selectively con-- nect one of said group of attenuator's in controlling rel 'lation between said generator and said reproducer, forward and reverse actuating means for said selector switch, means controlled by said switching device to apply actuat-- ing current for said actuating means in timed relation to said tone applications, a patient actuated switch determining the direction of actuation of said actuator means, a recording device operatively connected to said selector switch and means responsive to a predetermined number of tone applications for energizing said recording device. y

2. An audiometer comprising a tone generator operable to produce a plurality of tones, a tone reproducerl adapted to be applied to the ear of a patient, au attenuator connected between said generator and said reproducer and operable to match said generator and said reproducer, a switching device, means controlled by said switching device for intermittently applying a tone from said generator to said reproducer, a group of attenuators operable to provide a plurality of tone intensity levels, an intensityselector switch operable to selectively connect one of said group of attenuators in controlling relation between said generator and said reproducer, forward and reverse actuating means for said selector switch, means controlled by said switching device to apply actuat' ing current for said yactuating means in timed relation to said tone applications, a patient actuated switch determining the direction of actuation of said actuator means, a recording device operatively connected to said selector switch, a means responsive to a predetermined number of tone applications for energizing said recording device, a tone selector switch and operating means adapted to Iactuate said tone selector switch in response to a predetermined number of tone applications.

3. An audiometer comprising a source of a plurality of tones of preselected frequency, right and left ear phones, attenuator means adjustable to match each of the tones of said source with each of said phones, a tone selector switch operable to select a tone from said source, an attenuator device operable to provide a plurality of tone intensity levels, an intensity selector switch operable to select a tone level, a programming device operable to apply the selected tone to one of said phones for a predetermined interval, an intensity selector switch actu ating mechanism including forward and reverse coils, circuit means controlled by said programming device for applying actuating impulses to said actuating mechanism, a manually controlled relay operative to determine the coil energized by said impulse, a printing device including indicia selecting means operatively connected to said `intensity selector switch, actuating means operatively connected to said printing device, circuit means operative in response to a predeterminedy number of tone level presentations to energize said printing actuating means.

4. An audiometer comprising a source of a plurality of tones of preselected frequency, right and left earphones, attenuator means adjustable to match each of the tones of said source with each of said phones, a tone selector switch operable to selecta tone from said source, an attenuator device operable to provide a plurality of tone intensity levels, an intensity selector switch operable to select a tone level, a programming device operable to apply the selected tone `to one of said phones for a predetermined interval, anv intensity selector switch actuating mechanism including forward and reverse coils, circuit means controlled by said programming device for applying actuating impulses to said actuating mechanism, manually controlled means operative to determine the coil energized by said impulse, a printing device including indicia selecting means operatively connected to said intensity selector. switch, actuating means operatively connected to said printing device, circuit means operative in '75 response. toa predetermined number of tonelevel presen tatiana t@ @desde Said. Printing aduanas @sans ad, ating mechanism @tiembla cdnnsted. te' Saidy tous, selectur switch, said actuating means includins forward and reverse coils, circuit means responsive to a predetermined number of tone level presentations to energize said forivardcoil. i

5,. An audiometer comprising a source of a plurality of tones of preselected frequency, right and left earphones, attenuator means adjustable to match each of the tones of said source with each of said phones, a tone selector switch operable to select a tone from said source, an attenuator device operable to provide a plurality of tone intensity levels, an intensity selector switch operable to. select a tone level, a programming device operable tov apply the selected tone to one of said phones v for a predetermined interval, an. intensity selector switch actuating. mechanism including forward and reverse coils, circuit means controlled by said programming device for. applyingactuating impulses to said actuating mechanism, manually controlled relayy means operative to determine the coil energized by. said impulse, a printing device including indicia selecting means operatively: connected to said intensity selector switch, actuating means operatively connected to said printing device, circuit means operative in response to a predetermined member oliV tone level presentations to energize said printing actuating means, an actuating mechanism operably connectcd to said tone selector switch, said actuating means including forward and reverse coils, circuit means responsive to a predetermined number of tonel level presentations to energize said forward coil, circuit means responsive to a predetermined number of for-ward steps of said tone selecting switch to energize the reverse coil of said actuating mechanism.l

6. An audiometer comprising a source of a plurality of tones of preselected frequency,`right and left earphones, attenuator means adjustable to match each of the tones of said source with each of said phones, a tone selector switch operable to select a tonefrom said source, an attenuator device operable to provide a plurality of tone intensity levels, n intensity selector switch operable to select a tone level, a programming device operable to apply the selected tone to one of saidphones lfor a` predetermined interval, an intensity selector switch actuating mechanism including forward! and reverse coils, circuit means vcontrolled by saidprogramming d evice for applying actuating impulsesV to said actuating mechanism, manually controlledV switching` means operative to determine the coil energized 'by said impulse, a printing device including indicia selecting means operatively-connected to said intensity selector switch, actuating means operatively connectedfto saidprinting device, rcircuit means operative in response to a predetermined` tone level presentation to energize said printing actuating means, Y

:in actuating mechanism operably connected to said4^ tone selector switch, said actuating means including forward and reverse coils, circuit means responsive to apredetermined tone levell presentation to energize said for-ward coil-j circuit means responsive to a, predetermined` number oftorward steps of said tone selecting switchto energize the reverse c'oiljof said actuator mechanism, sa-id circuit means including in series circuit relation an. interrupter device anda liriit switch.

7. An automatic recording audiometer comprisingv a `tone generator operable to supplyv a plurality-ofLtones-n the audible range, a pair of earphones adaptedy to` be applied tothe ears orc a patiennja tirst attenuator adjustable to match each of the tonessupplied by saidgenerator a ith each otssaid phones, asecond attenuatonoperableto provide a plurality of tone intensities, ai, tone selector si. "ich operable toselectively-connect melones-of saidgencratorto one of-said. phones, anintensity level' selector switch operative to determinetthe intensitylevel offthe. tone, a programming device including aplurality ofiswitch actuating' means,l 'a' forward and: areverse, actuating coil f orsaid intensity level selector switch, a tone applying circuit controlled by Said programming device, a'swrins control circuit controlled by said programming device, a first and second impulse circuit successively controlled by said programming device, a patient response switch, a rclay responsive to the condition of said response switch for determining the connection of said impulse circuits to one of said forward or reverse actuating coils.

8,. An automatic recording audiometer comprising a tone generator operable to supply a plurality of tones in the audible range, a pair of earphones adapted to be applied to the ears of a patient, a first attenuator adjustable to match each of the tones supplied by said generator with each of said phones, a second attenuator t operable to provide a plurality of tone intensities, a tone selector switch operable toy selectively connect the tones of said generator to one of said phones, an intensity level selector switch operative to determine the intensity level of the tone, a programming device including a forward and a reverse actuating coil for said intensity level selector switch, a tone applying circuit controlled by said programming device, a scoringcontrol circuit controlled by said programming device, a iirst and second impulse circuit successively controlled by said programming device, a patient response switch, a relay responsive to the condition of said response switch for determining the connection. of said impulse circuits to one of said forward or reverse actuating coils, a rotating cam disc, a plurality of groups of switch actuating cams on said disc, said groups-of cams being unequally spaced apart on said disc.

9. An automatic recording audiometercomprising a tone generator operable to supply a plurality of tones in the audible range, a pair of earphones adapted to be applied to the ears of a patient, a first attenuator adjustable to match each of. the tones supplied by said generator with each of said phones, a second attenuator operable to provide a plurality of tone intensities, a tone selector switch operable to selectively connect the tones of said generator to-one of'said phones, an intensity level selector switch operative tov determine the intensity level of the tone, a. programming device including a forward and a reverse actuating coil for said intensity level selector switch, a tone applying circuit controlled' by said programming device, a scoring control circuit controlled by saidv programming device, artirst and second impulse circuit successively controlled by said programming device, a patient response switch, a relay responsive to the condition of said response switch for determining the connection offsaidy impulse circuits to one of said forward or reverse actuating coils, aprinting device including indicia corresponding-to the tonelevel determined by the intensity level selector-switch, an actuating coil for said printing device, a circuit-means operative in response to predetermined-number of ftonea-pplicationsrto energize said actuating coil for said printing device.

l0. An automatic recording audiometer comprising a tone generator operable tosupply a plurality of tones in the audible range, a pair ofearphonesadapted to be applied to the ears of a patient, a rst attenuator adjustable to match each of the tones supplied by saidgenerator with each-of'saidphones, a second attenuator operable to provideva. pluralityfof'tone intensities, a tone selector` switch operablelto selectively connect the tones of said generator tooneof 'said phones, an intensity` level selector switch operative.` todetermine the intensityv level of thetone, a programmingdevice including a forward and a reverse actuating coil for said intensity level selector switch, a tone applyingtcircuit controlled by said `programming device, a,scoringlcontrolicircuitcontrolled by said, programmingdevice, arrst and second impulse circuit successivef lyrcontrolledf bysaidI programming-1 device, a patient-re.- sponse switch, arelayresponsive to thegconditionof said response switch fordeterminingvv the connection of: said impulse circuits- -toY oneY ofsaidv forwardY or reverse; ac-

Ituating coils, a printing device including indicia corresponding to the tone level determined by the intensity level selector switch, an actuating coil for said printing device, a circuit means operative in response to a predetermined number of tone applications to energize said actuating coil for said printing device, a forward stepping coil operatively connected to said tone selector switch, circuit means responsive to a predetermined number of tone applications for energizing said forward stepping coil.

11. An automatic recording -audiometer comprising a tone generator operable to supply a plurality of tones in the audible range, a pair of earphones adapted to be applied to the ears of a patient, a rst attenuator adjustable to match each of the tones supplied by said generator with each of said phones, a second attenuator operable to provide a plurality of tone intensities, a tone selector switch operable to selectively connect the tones of said generator to one of said phones, an intensity level selector switch operative to determine the intensity level of the tone, a programming device including a forward and a reverse actuating coil for said intensity level selector switch, a tone applying circuit controlled by said programming device, a scoring control circuit controlled by said programming device, a rst and second impulse circuit successively controlled by said programming device,

14 a patient response switch, a relay responsive to the condition of said response switch for determining the connection of said impulse circuits to one of said forward or reverse actuating coils, a printing device including indicia corresponding to the tone level determined by the intensity level selector switch, an actuating coil for said printing device, a circuit means operative in response to a predetermined number of tone applications to energize said actuating coil for said printing device, a forward stepping coil operatively connected to said tone selector switch, circuit means responsive to a predetermined number of tone applications for energizing said forward Stepping coil, a reverse stepping coil operatively connected to said tone selector switch, circuit means including a limit switch and an interrupter for energizing said reverse stepping coil in response to a predetermined number of operations of said forward stepping coil.

y References Cited inthe file of this patent UNITED STATES PATENTS 2,257,263 Koren Sept. 20, 1941 2,394,569 Strommcn Feb. 12, 1946 2,537,911 Reger Jan. 9, 1951 2,563,384 Bekery Aug. 7, 1951 

